Preserving the original. Reconstructing its source code. Building its future.

OpenCol is an open-source initiative dedicated to reverse engineering, preserving, and modernizing Sid Meier's Colonization (1994).

Our work spans the original DOS and Windows 3.1 releases — reconstructing their source code, documenting their inner workings, preserving original gameplay behavior, and developing tools and ports for modern operating systems.

Our long-term goal is OpenCol: a modern, cross-platform evolution of the classic game, built upon a deep understanding of the original.

• OpenCol (planned) — The long-term project: a modern, extensible Colonization experience with gameplay improvements, bug fixes, and quality-of-life features.
• win-port — Native, cross-platform port of the original Windows 3.1 Colonization, preserving original gameplay behavior while running on modern operating systems without Windows 3.1 emulation.
• win31-runtime — Run the original Windows 3.1 version of Colonization on modern operating systems.
• mapedit — The original DOS map editor, running natively on macOS and Windows without DOSBox. Same screens, keys, and menus, and byte-identical .MP map files. Download the latest release.

• win-decomp — Reconstruction of the original Windows 3.1 game source code, with a focus on matching the original compiled binary.
• dos-decomp — Reconstruction of the original DOS game source code, preserving the behavior of the original executable.
• mapedit-decomp — Reconstructed C source of the original DOS map editor (MAPEDIT.EXE), compiling with Microsoft C 6.00A to the same machine code as the shipped program and using the developers' own function names.

• dos-tools — Extract, modify, and rebuild DOS game assets, including graphics, palettes, and text. Preview original maps and saved games.
• win-tools — Extract, convert, and rebuild game assets from the Windows release.
• fsm-to-mp — Convert FreeCol .fsm maps into classic Colonization .MP maps.
• sav-editor (WIP) — Browser-based editor for Colonization saved games.
• win-patches — Community patches restoring animated water, fixing bugs, and unlocking hidden features in the original Windows release.

• maps — Archive of community-created maps and scenarios.
• docs — Documentation of game mechanics, internal systems, and discoveries from reverse engineering.
• web-ui — Shared UI styles and components used across OpenCol web projects.

Whether you're a developer, reverse engineer, modder, artist, or longtime Colonization player, you're welcome to join the project.

Contributions can range from code and documentation to bug reports, testing, historical research, and sharing custom maps or saved games.

• Discord — Discuss development, share discoveries, and get involved.
• r/ColonizationGame — Connect with the Colonization community.

OpenCol is an independent fan-made project and is not affiliated with or endorsed by the original creators or rights holders. Original game files are not distributed; users must provide their own legally obtained copy where required.